Liquid crystal devices have been developed and used in a variety of applications, from computer displays to industrial uses. These devices are capable of a variety of functions, one of which is the ability to change optical properties with very low power consumption. Specifically, these devices may have a first, unactuated state, and a second actuated state, wherein the application of an electric potential or other physical stimulus causes the device to switch between the states. Removal of the electric potential causes the device to revert to the default state. Depending on the structure of the device, one state is less transparent or darker and one state is more transparent or lighter. Thus, a user may selectively darken the device, and, in the case of eyewear, darken the device that is associated with the eyewear.
Recently, liquid crystal devices have been put to use in outdoor goggles such as ski goggles. It has been found that associating a liquid crystal device with a lens of a ski goggle advantageously allows the user to darken or lighten the tint of the lens depending upon outside conditions. In other words, a user may prefer a darkened lens in bright sun conditions and a lightened lens in overcast or evening conditions. Such goggles are an improvement over prior art tinted lenses, but certain problems were realized in early designs.
Standard ski goggles typically include a front lens exposed to the exterior elements and a rear lens, which is closer to the user's eyes, wherein the front and rear lens are spaced apart by a gasket or the like. The liquid crystal device was disposed proximal the rear lens, facing the front lens. It was found that standard goggle constructions caused strain and stresses on the rear lens which were transferred to the liquid crystal device and, in turn, resulted in failures in the liquid crystal device. Specifically, the rear lens was usually tightly adhered to the gasket which was tightly adhered to the front lens which was held tightly within a peripheral channel. This configuration, while acceptable for normal goggles, caused flexing and other strains on the rear lens which contorted and ultimately led to the failure of some liquid crystal devices. Specifically, the electrodes used to connect an electrical power supply to electrode layers of the liquid crystal device were found to be quite susceptible to the aforementioned contortion, flexing and strains. Breakage of the electrodes results in a failure of the goggle that is very difficult to repair. And it was found that the electrical path between a power unit and the liquid crystal device was fragile and susceptible to failure, particularly in harsh outdoor conditions. Such failures were not easily remedied.
Thus there exists a need in the art to provide a liquid crystal ski goggle which reduces applied stresses on the liquid crystal device and further provides dependable and rugged electrical connection to a power source.